Flocked solvent activatable stiffening and shoe lining materials



s. M. GRISWOLD 3,022,188 FLOCKED SOLVENT ACTIVATABLE STIFFENING AND SHOELINING MATERIALS Filed Aug. 7, 1958 Feb. 20, 1962 I [rm/en for SlarzleyMGriswold B his fhzforne 'j C- w United States Patent() 3,022,188 BLOCKEDSOLVENT ACTIVATABLE STIFFENING AND SHOE LINING MATERIAIS Stanley M.Griswold, Newton, Mass., assignor to BB.

Chemical Co., Boston, Mass., a corporation of Massachusetts Filed Aug.7, 1958, Ser. No. 753,717 7 Claims. (Cl. 117-25) terial comprising aporous base impregnated in discontinuous form with a stiffener agentsuch as cellulose nitrate or polystyrene resin and hence adapted to besolvent activated to cause the material to become stiff afterevaporation of the solvent. Stiffener elements died out of such materialhave been used extensively for shoe toe stiffening. However, suchmaterial has had little use in heel end stifiening, particularly sinceefforts to provide a layer of flock on such material for use in unlinedshoes had proved unsatisfactory because the flock together with thelayer of flocking adhesive tended to crack on flexing of the materialand to peel away too easily from the underlying surface of the stiffenersheet.

It is accordingly an object of the present invention to provide improvedsolvent activatable stiffener material adapted for use in stiffening endportions of unlined shoes which will not have the above undesirablecharacteristics.

The material provided by the present invention comprises a single nappedfabric impregnated with a solvent coalescible stiffening agent indiscontinuous form and a layer of flock bonded to the unnapped side by alayer of adhesive which, instead of being superimposed on a layer ofstiffening agent covering the fabric, is directly engaged with thefabric surface.

ireferably, also, the flocking adhesive will be porous to minimizedanger of blistering the flock surface during solvent activation throughswelling of the flocking adhesive by certain solvents like toluol.

Certain method aspects disclosed in the present application are thesubject of a divisional application Serial No. 119,562, filed June 26,1961, in my name.

Further features and advantages of the present invention will best beunderstood by reference to the following description in connection withthe appended drawings, in which,

FIG. 1 is a counter died out of material made in accordance with thepresent invention;

FIG. 2 is a greatly enlarged partial section through a sheet of suchmaterial; and

FIG. 3 is a diagrammatic illustration of a method of manufacturing thematerial of the present invention.

Referring to FIGS. 1 to 3, the sheet material of the present inventioncomprises a base 10 of single napped fabric such as cotton flannelcarrying in discontinuous form a stiffening agent capable of beingcoalesced upon activation with a solvent. Conveniently, the material maybe prepared by passing the base through a bath 12 containing a liquidmixture of a stiffening agent in a form appropriate to deposit thestiffening agent in the base in a discontinuous form when the sheet isthereafter dried, Two well-known stiffening agents used in preparingsolvent activatable stiffener material are cellulose nitrate and3,022,138 Patented Feb. 20, 1952 polystyrene. Either of these agents maybe used although I prefer the cellulose nitrate because of its betteradhesive qualities. Where cellulose nitrate is employed as thestiffening agent, the fabric 10 is passed through the bath 12 containingthe cellulose nitrate 'dlSSOIVBd in a solvent.

After leaving the bath 12, the fabric is passed between stripping rolls14 which are adjusted to remove sufficient of the cellulose solutionfrom the unnapped side of the fabric so that after drying there is notsufficient stiffening agent left on this side of the material tocompletely cover the threads of the fabric thereby permitting theflocking adhesive to come into direct contact therewith. From thestripping rolls, if the stiffening agent is cellulose nitrate, thefabric 10 passes through a water bath 16. This bath is not employedwhere the stiffening agent is polystyrene which is preferably applied inthe form of the latex of the type disclosed in United States LettersPatent No. 2,760,884, issued August 28, 1956, on an application filed inthe name of George Leonard Graf, Jr. The fabric is then dried in adrying oven 18 and after passing over idler rollers 20, proceeds to aconventional flocking of the unnapped surface wherein a flockingadhesive 32 is ,ap-

plied from av trough 22 and flock 34'is applied from a second trough 24followed by beating with a bar 26. After this the stiffener materialpasses through an oven 28 to evaporate the solvent of the flockingadhesive and to cure it, and the finished material is then taken up on aroll 30. The layer 32 of flocking adhesive, shown in FIG. 2 applied inthis manner may be either porous or non-porous as desired. A porous filmof flocking adhesive is preferable to prevent distortion, blistering orswelling on contact with some solvents. To provide a porous adhesivelayer it is usually suflicient to employ a 10W solids and relatively lowviscosity adhesive such as #1734, a curing neoprene flock adhesive usingaromatic solvent, made by BB. Chemical Co., Cambridge, Mass. In somecases, however, a conventional flocking adhesive may be employed whereactivation will be performed by application of solvent only to theunflocked surface of the stiffener material.

The finished material may then he died out to form shoe lining elementssuch as the counter C shown in FIG. 1. In the dry form, this counter maybe flexed without cracking the flocked surface and the flock is sosecurely bonded to the fabric base as not to be easily removable.Previous efforts to flock such a fabric base impregnated indiscontinuous form with a stiffening agent had resulted in a materialhaving defects corresponding to the aforesaid good qualities of thepresent material which I believe arose because of the substantial layerof stiffening compound covering the fabric surface to which it was quiteloosely bound and which afiorded a very insecure surface for the flockanchorage through the flocking adhesive not only before but duringactivation.

Another advantage of the material provided by the present inventionwhich appears to bear some relation to the aforesaid non-crackingcharacteristic is that the material is less likely to fail at a seamthan material in which surplus stiffening compound between the fabricbase and the flock adhesive exists.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

l. Solvent-activatable stiffener sheet material for lining shoes and thelike comprising a base of single napped fabric carrying therein indiscontinuous form a solvent coalescible stiffening agent, and a layerof flock adhesively bonded to the unnapped side of said fabric, saidflock being free of said coalescible stiffening agent.

2. Solvent-activatable stiffener sheet material for lining shoes and thelike comprising a base of single napped fabric carrying therein indiscontinuous form a solvent coalescible stiifening agent, a layer offlocking adhesive directly engaging the unnapped side of said fabric,said.

flock being free of said coalescible stifiening agent and a layer offlock bonded thereto by means of said flocking adhesive; t

3. Solvent-activatable stiffener sheet material for lining shoes and thelike comprising a layer of single napped fabric carrying thereinindiscontinuous form a solvent coalescible stifiening agent and a layer offlock bonded to the unnapped side of said fabric by aporous layer offlocking adhesive, said flock being free of said coalescible stiifeningagent.

4. Solvent-activatable stiffener sheet material for lining shoes and thelike comprising a base of single napped fabric carrying therein indiscontinuous form a cellulosic derivative adapted to be coalesced bythe application thereto of a solvent, a layer of flocking adhesivedirectly engaging the unnapped side of the fabric and a layer of llockbonded thereto by means of said fiocking'adhesive, said flock being freeof said cellulosic derivative. 7

5. Solvent-activatable stiffener sheet material for lining shoes and thelike comprising a base of single napped fabric carrying therein indiscontinuous form a cellulose nitrate adapted to be coalesced by theapplication thereto of a solvent, a layer offiocking adhesive directlyengaging the urn-lapped side of the fabric and a layer of flock bondedthereto 'by means of said flocking adhesive, said flock being free ofcellulose nitrate.

6. Solvent-activatable stiffener sheet material for lining 4 V 7 shoesand the like'comprising a base of single napped fabric carrying thereinin discontinuous form a polymeric resin adapted to be coalesced by theapplication thereto of a solvent, a layer of flocking adhesive directlyengaging the unnapped side of the fabric and a layer of flock bondedthereto by means of said flocking adhesive, said flock being free ofsaid polymeric resin.

7. Solvent-activatable stiffener material comprising a base layer ofsinglenapped fabric carrying therein in discontinuous form a solventcoalescible stifiening agent, the surface of the unnapped .side of'saidfabric being substantially free from said stiffening agent and havingadhesively bonded thereto a layer of flock, said flock being free ofsaid coalescible stiffening agent.

References Cited in the file of this patent UNITED STATES PATENTS

2. SOLVENT-ACTIVATABLE STIFFENER SHEET MATERIAL FROM LINING SHOES ANDTHE LIKE COMPRISING A BASE OF SINGLE NAPPED FABIRC CARRYING THEREIN INDISCONTINUOUS FORM A SOLVENT COALESCIBLE STIFFENING AGENT, A LAYER OFFLOCKING ADHESIVE DIRECTLY ENGAGING THE UNNAPPED SIDE OF SAID FABRIC,SAID